1. Field of the Invention
The present invention relates to a semi-finished package and a method for making a package, and more particularly to a semi-finished package having a molding compound with a plurality of outer protrusions and a method for making a package by cutting the semi-finished package.
2. Description of the Related Art
FIG. 1 shows a cross-sectional view of a first conventional semi-finished package. The first conventional semi-finished package 1 comprises a carrier 11, a plurality of chips 12 and a molding compound 13. The molding compound 13 is disposed on a surface of the carrier 11 so as to encapsulate the chips 12.
The first conventional semi-finished package 1 has the following disadvantage. During a molding process, the molding compound 13 of the first conventional semi-finished package 1 is melted after heating, so as to encapsulate the chips 12. The carrier 11 and the chips 12 expand during the heating process, so that the carrier 11, the molding compound 13 and the chips 12 are combined under high temperature. However, the coefficients of thermal expansion of the above-mentioned devices are different, so the shrinkages of the carrier 11, the molding compound 13 and the chips 12 are different after the molding process is finished and the temperature is lowered, which leads to the warpage of the first conventional semi-finished package 1, as shown in FIG. 2. Moreover, since semiconductor packages are getting smaller and lighter nowadays, the carrier 11 and the molding compound 13 are getting thinner, and the warpage is getting more serious. The overly warped semi-finished package 1 will cause various problems, e.g., it will stick on tables, it will be difficult to hold the package, laser marking will fail, it will be difficult to form solder balls, some solder balls will be missing, the package unit will be overly warped and coplanarity will not exist.
FIG. 3 shows a cross-sectional view of a second conventional semi-finished package disclosed by U.S. 2004/0029318. The second conventional semi-finished package 2 comprises a carrier 21, a plurality of chips 22, a molding compound 23 and a plurality of cutting lines 24. The molding compound 23 is disposed on a surface of the carrier 21 so as to encapsulate the chips 22. The molding compound 23 has a plurality of slots 231 disposed over the chips 22.
The second conventional semi-finished package 2 has the following disadvantage. The second conventional semi-finished package 2 is cut into a plurality of package units 25 after it is cut along the cutting lines 24. However, the molding compound 23 of each package unit 25 still has a slot 231, which influences the appearance of the product.
Therefore, it is necessary to provide a semi-finished package to solve the above problems.